Isn't s and t switched in the image? If i is the x coordinate s should be horizontal right?
I think if we interpolate vertically first, we would get the exact same result.
Vertically interpolating will only change the order of the operation, but in such a way that it doesn't change the actual output.
Does this mean that we sample at the corners of the pixels?
I think the order of interpolation doesn't matter.
If the vertical pixels are blended first, the final result should be the same.
The final result would remain the same.